Gas-fired refrigerator



Allg. 18, 1936. M SHQELD 2,051,318

GAS FIRED REFRIGERATOR Filed Oct. 5, 1933 2 Sheets-Sheet l x. ma l la.

Aug. 1s, 1936. M, sHoEL-D 2,051,318

GAS FIRED REFRIGERATOR Filed Oct. 5. 1933 2 Sheets-Sheet 2 ,In/ven ion Patented Aug. 18, 1936 UNITED STATES PATENT oEFlcE 11 claims.

The purpose of this invention is a gas-med, aircooled, domestic refrigerator.

The primary advantage of a gas-fired refrigerator is its absolute silence and its freedom from wear. 'I'his invention makes it possible to produce a machine of this type at very low rst cost and one that is very economical to operate.

In addition to the above, the major quantity of ammonia is always present on the low pressure side of the machine, which is of great advantage from a safety standpoint.

The only thing required for the operation` of the machineis a small continuous gas flame. If desired the apparatus can be put in the cellar with the refrigerator in the kitchen on the next floor. The apparatus itself is, however, very compact and ts into a tiny space behind the refrigerator.

One object of this invention is an absorption refrigerator with a high pressure side and a low pressure side and with an intermittent generator, where the generator discharge and filling cycles are so short that the generating cycle is in operation nearly all the time.

5. Another object of this invention is an extremely small heat capacity of that part of the intermittent generator, which comes in contact with the liquor. This without the sacrifice of any structural strength of the generator.

' Yet another object is a short cycle intermittent generator with a continuous heat supply.

Referring to the accompanying drawings: Fig. I is an elevation of the entire refrigerating machine; Fig. II is a somewhat enlarged cross section of Fig. I at AA; Fig. III is an enlarged vertical cross section through the center of generator g, shown in Fig. I; Fig. IV is a horizontal cross section of Fig. III at B-B; Fig. V is an enlarged vertical cross section through the center '40 of heater h, shown in Fig. I; Fig. Vi is a horizontal cross section through heater h., as shown in Fig. V.

Fig. I shows a sideview of the entire assembly. This drawing is partly diagrammatic, but it is drawn to scale, so that the proper proportion of the various parts can be visualized. Referring to this drawing, g is the generator, h the heater, which in its operation is an integral part of the generator. r is the rectifier, c the condenser, e the evaporator and a the absorber.

The absorber a consists of two legs of standard 3', steel pipe with an overall height of 60". These pipes are provided with copper fins f, which is also indicated in Fig. II, which is a cross section at A-A of Fig. I. The 3" pipes are intercon- (Cl. (i2-5) nected at top and bottom with short pieces of 3" pipe, making a complete loop. A little below the top is another interconnection between the legs, the reason for which will be described later.

'I'he evaporator e is shown on the side. In ac- 5 tual practice this part is of course in the ice box and would be behind the other apparatus.

The ilow of the refrigerant is indicated with arrows, but merits the following preliminary explanation. The liquor in the generator g, during the generating cycle, is recirculated through the heater h, through pipes 5 and 4. Pipe 4 delivers a mixture of gas and liquor. Through pipe 6, the generator is charged with strong liquor and the weak liquor is discharged through pipe 1 to 15 the absorber. These two pipes may under conditions be combined into one. The reason for using two pipes in this 4case will be shown later.

The gas from the generator passes through the rectifier 1-, which is equipped with copper fins, The rectied gas goes through check-valve ch through pipe 3 to the condenser c, the construction of which will be described later. The condensedl liquid ammonia goes through pipe 2, through a springloaded expansion valve ex into the evaporator e. ic indicate ice-cube trays. The 4ammonia gas from the evaporator leaves through pipe I and goes to the absorber a.

` b is a gasburner which burns steadily and continuously. The refrigerating y effect as will be shown is a function of the size of the gas flame. The generator and heater assembly g and h is packed in insulating material as for instance infusorial earth or magnesia. This is indicated by i. s is the stack for the flue gases from the gas burner. This sheet iron stack is insulated with asbestos.

s is a stove pipe stack to carry away the hot air from around the rectifier fins. This air is warmer than the air from either the absorber or the condenser and it is carried away separately to the top of the machine so as not to interfere with the cooling eiciency of the absorber and vcondenser iins.

The generator-heater assembly is the heart of the machine andv it will now be described.

Al detail of a vertical cross section through the center of the generator g is shown in Fig. III. This drawing is also to scale. vThe inside diameter is 41A!" and the inside height 5 1/2". A horizontal -cross section at B-B is shown in Fig. IV.

il is a pressure `resisting vsteel shell. The top I2 is shown bolted on. The numeral I3 indicates bolts. An aluminum or hard-lead gasket Il is countersunk as is common practice in am- 55 Y black sheet should be used monia iiange fittings. It should be noted, however, that the ltop of fact the entire refrigerating apparatus assembly is welded steel.

An inside shell I5 of thin tin plateisprovidedand spaced evenly from the outside pressure resisting shell. 'Ihe top lof the inside shell is soldered 'to the outside shell at I6. Suitahly a high melting point solder or pure tinsolder should be used `for this purpose. If th'e top I2 .is welded on,` it is of course necessary to -`also use weldling for the inside shell'lnstead of solder. .In this case thin for the inside shell instead of tin plate. `A small utin" pipe I'I `leads from the bottom of the space between the twoshells at I8 to `approximately the top of the inside sneu. i .l

I9 is a .cylindrical iloat valve with open bottom, which can slide up and down in vertical direction on small tin", pipe .or aluminum'rod. Stops 2l .and l22, which are small discs f to 2l limits the travel of the iloat in' relation to the center rod 20.- The iioat position in Pig. III is its highest position. When disc 23, which is an integral part of the lloat, strikes disc 2l, the low position of iloat vs. rod is obtained.

The rod 2n carries valves 2l and 25 through pin joints 2i and 21. The travel of these valves is limited to 1A," and each is provided with its own guide as indicated. As will be shown later, these two valves are never open at the saine time.

When one is closed the other one isopen.

Disc 23 also operates liquor discharge needle valve 28 through leverage arm 23. A screen s: is provided to prevent any clogging of the needle valve.

30 is a check valve at end of liquor line-6, which furnishes strong liquor to the generator from the absorber.

r is the rectiiier. which consists of a 1" extra heavy steel pipewelded to the top I2 of the outside shell. It is provided with packing 3|, which may consist of steel ball-bearing balls.

A vertical cross-section of the heater h is shown in Fig. V and a horizontal cross-section in Fig. VI. These drawings are also to scale but shown in half size of Fig. III. The heater consists of a cylindrical piece of iron casting 5" diameter and 6" high with a spiral of two loops of Va" extra heavy steel pipe cast into the periphery. 'I'his pipe ends up as pipe 4 and 5, the latter taking the liquor from the generator and the former delivering gas and liquor to thev generator. This circulation of liquor is very rapid due to the "airlii't" etIect of the gas produced in the heater section of the4 pipe. 'I'here are seven vertical 1/2" fluesin the center of the casting. 'I'he heater rests on a refractory ring 32.

Going back to the generator in Fig. III.` the dotted lines 33 and 34 indicate respectively the maximum and minimum level of liquor, corresponding to the beginning and the end of the generating cycle. 'I'heposition ofthe iloat in Fig. III shows that the generating cycle is about to start or is proceeding. This means that the4 liquor level is somewhere above the 34. As indicated, valves 25, 28 and 30 are closed and valve 24 is open. Theliquor leaves thev generator through pipe 5 and liquor and gas are returned through pipe 4. Pipe 4 terminates right inside i the iloat, which acts vas a splash or separating the liquor The end of line 4 is arranged so that and gas discharge is horizontal. `The the inside of the float through pipe I0,

chamber.

gas leaves may be welded on'. As a matter f charged the pressure inside `the entire iloat assembly el of these valves is t".

which starts slightly skirt ofthe iloat.

As the gas generation cycle proceeds, the liquor level recedesuntil it iinally reaches level 34.. At

above the lowest level of the this point the weight of the float is suillcient to f open valve 28 through leverage arm 29. The weak liquor leaves through pipe l and is delivered to the absorber. After all the liquor has been disand any condensate thathaslormed in the space between the shells is ejected through pipe I1. The v.heater pipe is also cleared of liquor. the pressure dro further to a predetermined point, in this case 20# per square inch pressure diirerential between high and low side, the weight of the float assembly makes it drop, opening valve 25 as it closes valve 24. Line 3 is a vent line which connects the top of the generator with the gas space above -the liquor in-the absorber. As soon as the preures between the high and the low sides have approximately equalized. check valve 3l opens due to the hydrostatic head of about four "6. Some ofthisliquoralsooomesinthroughpipe the generator drops It Vmight be mentioned here that there is conn stant circulation of liquor in the absorber due to thermosiphon'action. It shouldbe noted that the entire heat input into the absorber is at the lowest part ofthe right hand leg. .This `heat input is from the hot weak liquor as well as from the absorption of the ammonia gas from the evaporator,

which is introduced into the absorber through pipe I. On account of this automatic circulation of liquor in the absorber, the weak liquor introduced into it through pipe 'I gets mixed up rapidly with the entire amount pf liquor in the absorber. The quantity of liquor present in the absorber is about 30 times as large as the quantity of weak liquor discharged from the generator in each cycle.

To 'prevent any slight noise when theweak liquor is discharged into the absorber, the pipe I running to the' absorber .may be extended into the absorber in the form of a coil or return bends. -This will precoci the hot weak liquor and'any gas produced by the sudden pressure release' will be condensed before it -mixes with the liquor. in the absorber.` Any'slight hissing noise oriiice of valve 23 during the weak liquor discharge is effectively eliminated due to the fact y that the generator is surrounded with insulating material. ,1 As the liquor level rises in the generator during the illling cycle, valve 24 is kept closed dueto the hydrostatic head in the generator until the top level 33 is reached, when the lifting powerof the float is sufficient to counterbalanee this hydrostatic head. `'I'he diameters of the float and the foot valve ar'e so` chosen, that at liquor level 33' the lift of the float corresponds to the weight of 24 snaps open as 25 liquor. At this point valve closes. vAs mentioned before the maximum trav- I At the same time valve the heater starts as soon as valve 24 opens. Presplus V4 of an inch extra sponding to '15# ice ,open. If for any reason an (not shown in draw- Iis located in the back of the icebox, a usual bimetallic thermostatic gas shutoff control is provided to shutoff the gas in case the flame blowsput. If the apparatus is located in the cellar, the stack s is connected to the regular house chimney and the last mentioned safety arrangement is not required. The gas flame ison the order 'of only 3 c. ft. of 550 B. t. u. gas per hour for a refrigerating capacity correper day. The average gas consumption is less than 550 B. t. u. gas.

Another safety control may be provided if so desired. This lconsists of a copper rod fastened to the heater casting h and extending out slightly beyond the insulation. At the end of the rod a fusible alloy link and wire is attached. This wire holds a spring valve of the gas supply line excessive temperature is developed in the heater, the fusible link Vwill part and shut off the gas.

The preferred expansion valve is bf the spring loaded type and acts also as a safety valve for the high side. The high side' of the apparatus is of relatively very small volumetric capacity in comparison to the low side.

vGoing back again to the generator shown in Fig. III, line 9 is a small auxiliary pipe directly connected with line 5 below valve 2l and extend ing slightly inside the float I9. The reason for this pipe connection-is the following. After prolonged shut downs it is possible that due to any small leaks in the float it will ll or partly ll with liquor and settledown and close valve 24. In this case, when lighting the burner to start the refrigerator, liquor will be supplied tothe heater through pipe 9. The gas and liquor discharge from pipe 4, will fill the float with gas and 1 refrigerator legs,

- velocity vover the ns.

lift it, after which normal operating conditions ensue. In addition to using the inside` of the float as a splash chamber, this is the reason for locating discharge end of pipe 4 in or under the float.

Before giving .detailed data of performance of this machine under specific conditions. some further descriptions of various parts will be given.

L The copper ns f of the absorber a shown in Figs. I and 1I extend the entire height of the refrigerator proper, that is minus the height of the which are not shown. The outside ends of the tin plate sheets 35. The purpose of this is to produce a stack effect by drawing in cold air from near floor level and discharging the warm air at the top of the refrigerator. creases 'the heat transfer coefficient between the copper fins and the air, due to the increased air By far the largest amount of total-heat to be dissipated is from the absorber.

corresponding to 75# ice per 'Ihe lever of the cock is hooked upto a dial 1000 c. ft. per month ofl ns are closed off with vertical This stack effect inare arranged to take a minimum of airspace away from the copper ilns. For this purpose the pipes are flattened to oval shape where they go through a split part of and are centered on a fin.

When generator g has just finished discharging liquor to the absorber a,

top W'hen the generator has just been filled, the liquor level in the. absorber' is at its minimum.

The large pipe connection 36, shown in Fig. I, be`y the liquor in the absorber takes place at all times- Valves v, v1 and v2 are for the purpose -of -evacuating and lling the system with its original charge of ammonia and ammonia liquor.k For this purpose a vacuum as'nearly complete as possible is pulled at valves v and vz. Liquid anhydrous ammonia is then introduced at v2 until a pressure gauge at vi shows acertain predetermined pressure. Then ammonia liquor is introduced at v until it overflows at v1. sorber is full of liquor to the top and the .generator is full up'to the top liquor level allowed by the float. Now a quantity of liquor is withdrawn from valve v, which quantity is somewhat larger than the volumetric liquor capacity of the generator g. The system is now lled and ready for operation.

At this point it may be well to explain the pur- At this point the abthe liquor level y of the absorber is at its maximum and near the pose of the inner shell i5 in generator g, shown in Figs. HI and IV.

Just after the weak liquor has been discharged from the generator,'the generator itself is of course at maximum temperature. When the strong liquor from the absorber a comes 'i'n' through pipe 6 to the generator g, the inside shell only will be cooled down. This cooling of the shell (as well as float and valve assembly) is of courseaccomplished by evaporation of a small quantity of ammonia from the strong liquor,'

which returns to the absorber through vent line 8. The quantity of ammonia evaporated in this manner is a function of the heat capacity of the inside shell, float and valve assemblies inside the generator. v By using an inside very light shell it will be shown later that the actual quantity of ammonia lost from the strong liquor to the absorber during the filling' cycle is very small. Referring to the rectifier r shown in Figs. I and II, it was previously mentioned that this consists of a piece of extra heavy 1" steel pipe lled with ball-bearing vsteel balls as packing and provided with radial copper fins f. 'I'he coppose lines 2 and 3 may be made from extra heavy 1,43" steel tubing with a steel wire in the'center,

filling most dfsthe pipe. The condenser itself 'is made from twov pieces of pipe. The outside one is a 3" extra heavy steel pipe and the inside one is made for a slide fit. A relatively widely spaced thread is cut on the inside pipe which thread constitutes the'passage for the ammonia. Top

and bottom as well as all connections are flame refrigerant between the shells. It is arranged so l that there is no chance for any water carried over with the ammonia to accumulate. The liquid ammonia enters through the expansion valve at the top. Rods or pieces of wire are welded lengthwise to theA top half of the insideshell and to the bottom half of the outside shell to pro-l vide a zigzag path for the `ammonia 'as it runs down both sides off-the.`;evaporator. The am'- monia gas leaves fromfthe lowest; point.- ANo v check valve is requiredymqme' from the emporator to the absorber. f

When afloat controlis in generator g toy operate the Weak liquorv'dischargevalv'e 28, the expansion valve ex. is ofthe spring loaded type, which maintains a predetermined maximum pressure differential between the -highA side andf the low side. This means that the required pressure exerted on the leverarm 29 by float I9 to,

open valve 28 is always the` same. This in turn is a function of the liquor levelin thejgenerator.

Ar predetermined liquor .levelin thefgenera'tor at which point dischar evvalv the ammonia conc is always the sameQwh'enf-i stdischarged into the absorber. y The above is the pr y H 28 can, however, a1so"bef operated by means of a thermostat, either 'bimetallic' or sylphon'. In

this case the expansion valve is'o'flthe diaphragm type, with one side of the diaphragm` exposed to the atmosphere and the other side to the high pressure side. Any springiused for: initialxsetting is in this case located on the* atmosphericside oi' the diaphragm. 'I'his means that Ithe. ex.- pansion valve operates onlyA on a predetermined. basis of absolute'pressure in thegenerator. lWith the absolute pressure constant'in,v theg'eneraf tor during the generating cycle, the' ammonia concentration in the liquor is only a functionfof the temperature. With predetermined setting oi the thermostatic valve control, the weak liquor discharged to the absorber willalwa'ys be' of the same ammonia concentration.

'I'he importance of maintaining predetermined ammonia concentrations of both the strong and the weak liquor is due to the fact that this is the governing feature of the etllciency'of the refrigerator.

1 The spring loaded expansion valve ez in case of the refrigerator shown in .the drawings operates when a Ypressure differential of 200th per square inch exists between the high and the low side. The force required tolli-t the liquor discharge valve 28 is one pound. The net area of A the discharge line at valve 281s 0.005 sq.'in. or 0.08" da. Theieverage used in arm 23 is 1:4. The net weight of the oat IIl) when the liquor level is at 34 is At the moment valve 28 springs open, the pressure in line 1 and inthe valve orifice is immediately increased. This causes the valve 28 to spring open ywithout hesitation. The travel of the float is from disc 23 to vdisc 2| or about which means that the vertical distance that valve 28 opens is 116" during the liquor discharge cycle. When the pressure differential between the high and the low side has dropped to 20# per square inch, the entire float assembly drops, ing valve 24. At this point-all weak liquor has of course been discharged from the generator.

' makes the specic gravity of .opnsgmeans that s rredarrangement. Valve opening valve 25 and c los-v The weight of the sont itseu is 15o grams and the weight of the entire iloat assembly is 225 grams or about l/giih Thus net dia. of opening in pipe at valve 25 is 0.18.

The above given figures determine the oat dimensions to produce the maximum and minimum liquor levels 33 and 34. The level 34 is 10.8 centimeter above the bottom and the distance between 33 and 34 is 3.2 centimeters. The diameter ofthe iloat is 7.2 centimeters and the height 6.2 centimeters. The distance from the top of the float shown in the position of Fig. III to liquor level 33 is` 1.5centimeter.

It should have been mentioned previously that the concentrationA and temperature of the strong and the weak liquor in this case are respectively 36% and 19% NH3 at 114- and 300 F. This both about the same or about 0.86.

The diameter of the foot valve 24 or rather the diameter of the opening underneath is H". This means that to open this valve at the end of the lling cycle a hydrostatic head of V4" liquor is .required above the liquor level balancing the weight of the entire iloat assembly. The travel of valves 24 and 25 is 5/8" as previously menthat there will be nohesitation in making the full stroke either up or down. v l -Tne total weight of the charge of strong liquor v-v,in the generator-at the beginning of the generating cycle is-1.5#. The total amountof weak liquorl per cycle is 1.241%.

Aspeciic example of a severe operating condi- 'I'he amount of ammonia available for refrigeration: 0.3# per cycle.

tion and the eiilciency of this refrigerator will now be given.

Room temp.. Fs-Absorber and condenser temp.: F.Pressure diiferential between vhigh and low side: 200# per square inch-Condenser pressure: 247`# aba-Absorber and evaporatorf pressure: 47# abs. Liquor concentration in absorber: 36.7% NH3 by wt.-Evaporator temp.

(It should be noted that with 'the temperature inthe. absorber normal or 80 F. fora 70 F. room temperature, the absolute pressure in the ab'- .sorber and the evaporator willbe 26#, corre-. spondingto an evaporator temperature of f6 1".4

Obviously the NH3 concentration of the liquor in the absorber and the diierential pressure between the high and the low side may be chosen -A to suit any desired evaporator temperatureunder given conditions.) 4

Temperature of weak liquor in generator right' before discharging to absorber.: 300 F.-Concen tration of `weak liquor: 19.1% NH3 by weight.- Amount of NHalost during the filling cycle: 0.88% by weight of stnong liquor. 'Ihis is based upon '1.5# of strong liquor per charge and `total weight of inside shell in generator plus weight of, entire float assembly and valvesv of 0.7#. Net amount of ammonia available for refrigeration per 1# strong liquo i 0.207#. Concentration and temperature of liquor at end of charging period: 35.8% NH3 by wt. at 113.5' F.'- Temperature at which NH; condenser under 247# abs. pressure; 215 F. The following figures are `on the basis of one pound yof strong liquor in the generator at end of charging period. l

Amount of weak 0.793#.Net amount eration: 0.207#.Am rectifier: 0.021#. i'

starts' to go Ato 'then Heat required to raise temperature of liquor: 194.5 B. t. u. Evaporate and superheat 0.207# NH3:10B.9 B.t. u.-Evaporate 0.021# water: 19.3 B. t. u.-Total heat input per one pound of strong liquor: 322.7 B. t. u.

Refrigeration produced. by 0.207# NH3 under the conditions given: 94 B. t. u. Thus thermal coeicient of this refrigerator under the above conditions: 29%.

With normal condenser and absorber tempera'- ture the thermal coefficient would besomewhat higher.

Using 550 B. t. u. gas as heat supply at 80% emciency, it takes one c. ft. of gas to produce the refrigerating effect of one pound of. ice, under the conditions given. This is a very higheiciency for an air-cooled, gas-fired, domestic refrigerator.

As previously mentioned,v for '75# ice per day, the generating cycle is 20 minutes, the emptying and iilling cycle 30 seconds.

The weight of the cast iron heater is about 35#. With heat input corresponding to '75# ice per day the rise in temperature of the heater during the filling cycle is less than 3 degrees F.

The heating coil in the heater has a surface large enough to require less than 10 degrees F. temperature difference between the liquor and the metal to produce '75# ice per day.

The heat capacity of the liquor in the absorber and the absorber itself is such that when one charge of weak liquor is dumped into it, the temperature rise is less than 6 degrees F.

In the above mentioned case of 100 F. room temperature and 75# ice per day, the mean t'emperature of the absorber is 110 F.` The minimum is 107 F. right before the end of the generating cycle and the maximum 113 F. right after a charge of weak liquor has been dumped into it.

The radiating surfaces indicated for the absorber, rectifier and condenser are ample to take care of the condition in question.

Those skilled in this art will understand, that this invention ls not necessarily restricted to the precise and exact details of the apparatus described, because these are subject to more or less radical modifications without departure from the substance and essence of the invention as defined by the appended claims and without sacrificing any of its substantial benets and advantages.

I claim: f

1. In an absorption refrigerating apparatus v with a high pressure side and a low pressure side,

an absorber; a condenser, means vfor supplying heat to liquid in one part of the apparatus, means for transferring said heated liquid to a second part of the apparatus, said second part being provided with a conduit to conduct refrigerant to the condenser and with means for transferring liquid'to the absorber.

2. In an absorption refrigerating apparatus as set forth in claim 1 and including heat accumulator means as an integral part of said first part of the apparatus.

3. An absorption refrigerating machine'with an intermittent type generator and a continuous heat supply, the generator assembly r,of which consists of a container, a heating device, conduits cyclically connecting said container directly with said heating device, and means for intermittently clasing the passage way of said conduits, said heating device being provided with a heat accumulator.

4. An absorption refrigerating machine as set forth in claim 3, the heat capacity of said heat ing means to periodically shut off to the generator, means absorber; means for co intermittently V an intermittent type generator, assembly of which consists of a container, a heataccumulator being at least ten times as large as the heat capacity of the total amount of liquor present in the heating device at any time.

5. In an absorption refrigerating machine, an intermittent generator, said generator consisting of a container, a heating device, and conduits cyclically connecting said container with said heating device; means for circulating liquor from the container through the heating device and back to the container; a valve and valve operatthe flow `of liquor through the heating device, said valve and said valve operating means being entirely en'- closed within said container.

6. In an absorption refrigerating apparatus, an intermittent generator, a continuous heat supply which heats a liquid circuit cyclically connected for intermittently stopliquidin said circuit; an pletely preventing transfer of absorption liquid between the generator and the absorber during the generating period and means for substantially emptying the generator during leach cycle of operation.

7. An absorption refrigerating machine with an intermittent type generator, the generator assembly of which consists of a container, a heating device, and conduits cyclically connecting the container directly with the heating device; means for circulating liquor the heating device and directly back to the container; an absorber; and means for intermittentlydischarging to the absorber substantially all the liquor in the container, the heating device and the conduits.

8. In an absorption refrigerating machine with ahigh pressure side and a low pressure side,'an

ping the circulation of intermittently operating generator, a continuous and' conduits cyclically connecting the containerl with the heating device; means for circulating liquor from the container device andback to the container; periodically preventing ow of liquor thrugh the heating device, during the period when the container is being filled with a fresh charge of strong liquor; and a second valve means to vent the top from the container' through' through thev heating valve'means for of the container to the top of the absorber during said filling period.

10. ln-absorption re rigerating machine with the generator ing device, conduits cyclically connecting said container with said'heating device; means for circulating liquor from the container through the heating device and back to the contain an absorber; valve means located entirely within said container, said valve means being'operative to discharge an entire charge of weak liquor from the container to the absorber at a predetermined point of ammonia concentration in the weak liqwithin said container, said second` valve means being operative to vent the top of the container to the top of the absorber at a predetermined point uor;`and asecond valve means located entirely Yof pressure difference betweenthe kcontaine'el and container and the absorber; a second valve means connecting' the container withthe heating device..

Aan intermittent type located entirely within the container, saidseccnd valve means being operative in conjunction with said iirst mentioned valve means, said second valve means being operative to close the outlet conduit from the container to the heating device.

12. In an absorption refrigerating apparatus, an intermittent generator, said generator consisting of a container provided with a heat insulating liningV a heating pdevice, and conduits cyclically 13,-An absorption refrigerating machine with generator, the generator assembly of which consists of a container, a heating device, and conduits cyclically connecting the container with th`e heating device, said 'container being provided with an inside shell of relatively thin metal spaced from the outside pressure resisting shell. y

14. An absorption refrigerating machine as set forth in claim 13, and including an open c0nnec' valve means lotion between the inside'of said container and the space between the two shells; and means to discharge at each cycle any condensate lformed in the space between the shells.

15. In an absorption refrigerating apparatus,

an intermittent generator, said generator consisting of a container provided with a heat insulating lining, a heating device. and conduits cyclically connecting` said container with said heating device, the outside of said container being heat insulated from said heating device.

16. An, absorption refrigerating machine, the

generator assembly of which consists lof a container, a heating device,vand conduits cyclically connecting said container with said heating device; said container being provided with an open oat valve control; the conduit from the heating device to the container terminating under or inl side the iioat, substantiallyas described.

1'7. An absorption refrigerating machine,A the generator assembly of which consists of a container, a heating device, and conduits cyclically connecting said container with said heating device; said container being oat valve'I control; an auxiliary liquor supply conduit from the container to the heating device,A

the inlet of said auxiliary conduit extending inside the said float, to eliminate any liquor -accumulation inside the float, substantially as set forth. v

L MARK SHOELD.

provided with an open 

